As a matter of fact, it wouldn't be the dept of the water in this case, but rather the height at which you jump. The higher you go, the faster the velocity and water starts to get pretty damn hard from that height. If it's high enough it would brake bones and detach limbs...

Since moving to the US from UK, I have gone cliff jumping with some friends here. I jumped from maybe 35-40 feet, and yeah it kinda hurts when you don't hit the water cleanly.

HOWEVER, if you guys think that these guys are crazy here...check out a news article from one of my county's local newspapers back in England. Bored kids are 'tombstoning' from TWO HUNDRED yes TWO HUNDRED FEET. I don't understand why they are not dying...the impact along must be incredible.

CruelHM that's pretty fucking weird you say that about tombstoning. I live in Canada now but i'm from Plymouth in Devon. We used to do that every summer from Bovisand. The name Tombstoning came from a jump on the hoe called "Tombstone" The evening Herald used to run the same story every year about it.